I actually have switched to Mobil Synergy, away from Optimax, as the Optimax seems to leave a film and residue across the back of the car, which even detergent struggles to remove.
A freind of mine, who was using it in his drag boat reported the same thing.
In addition, the quality of Optimax seemed to go up and down, it wasnt consistent. However, Synergy seems to do the trick. No complaints
Chevs may go, but theres nothing like a HO!
Proud LSUG Member, and 9" Nodular Iron driveline test pilot.